WM_QUERYENDSESSION

[microwaved]

I need to detect that the user logged out of Windows so I can exit my program gracefully. The ni site said there were Windows Event Queue vi's that could be used to catch the WM_QUERYENDSESSION message, but I haven't been able to find them. Maybe there is a better way to do this?

[FLX]

Hi,

if you search with google for "Windows Message Queue Library LabVIEW".

You should come to this link.

Windows Message Queue Library

In the readme you find the message numbers, too.

#define WM_QUERYENDSESSION 0x0011

good luck :thumbup:

alex

[jed]

I would love to do this, but I need to delay the shutdown:

Any idea how to delay it until I am done with some housekeeping?

Or can I figure out exactly what the shutdown params are (shutdown/restart/etc), then cancel it, do my thing and reinitiate it?

[AdamRofer]

QUOTE(jed @ Sep 11 2007, 01:26 PM)

I would love to do this, but I need to delay the shutdown:

Any idea how to delay it until I am done with some housekeeping?

Or can I figure out exactly what the shutdown params are (shutdown/restart/etc), then cancel it, do my thing and reinitiate it?

I keep a shortcut on my desktop to "C:\WINDOWS\system32\shutdown.exe -a" which aborts any shutdowns that I notice quickly enough. I'm sure a Windows DLL alternative is out there but calling this should work as well.

[Rolf Kalbermatter]

QUOTE(jed @ Sep 11 2007, 04:26 PM)

I would love to do this, but I need to delay the shutdown:

Any idea how to delay it until I am done with some housekeeping?

Or can I figure out exactly what the shutdown params are (shutdown/restart/etc), then cancel it, do my thing and reinitiate it?

The Windows message queue example is not really meant to hook directly into the queue but only monitor it. In order to hook into that event you would have to modify the C source code of that example to do that specifically. Not to difficult but without some good C knowledge not advisable.

Another way might be that newer LabVIEW versions will send a filter event in the event handling structure "Application Instance Close?" which you can use to disallow shutting down the app. Not sure if it will disallow shutting down the session directly though. But it should be enough to detect that there might be a shutdown in progress and allow you to execute the command Adam mentioned to abort that.

Rolf Kalbermatter